The invention relates to a valve system in general, and in particular, to a valve shutter system for the control of fuel/air intake and exhaust dispersions from a cylinder containing a piston commonly found in an internal combustion engine. The valve shutter system includes a shutter assembly having a shutter cage including a plurality of apertures arranged along the circumference of the cylinder head and a shutter ring having corresponding apertures of similar size which rotate to align and close the shutter cage apertures for regulating the intake and exhaust cycles of the internal combustion engine.
In the standard automobile, the automobile is powered by an internal combustion engine turning a crank shaft and consequently the fly wheel. In an internal combustion engine, the combustible fuel burns inside the engine taking place within a cylinder. In the cylinder a piston, which is connected to a crank shaft through a connecting rod, oscillates up and down during its operating process. The cyclical movement of the piston moving up and down powers the crank shaft. This cyclical movement in an automobile engine is generally termed as a four stroke cycle.
The four stroke cycle in a gasoline engine includes the intake stroke, the compression stroke, the power stroke, and the exhaust. In order to maximize the conversion of heat energy from the combustion to mechanical energy of the piston turning the crank shaft, the combustion occurs inside a cylinder. The cylinder is closed during the combustion.
Accordingly, the cylinder head has an intake opening and an exhaust opening for allowing the fuel/air mixture to enter the cylinder and for exhaust to exit the cylinder. In order to maintain the cylinder in a closed condition on the firing of the combustible fluid, valves are used to open and close the intake and exhaust openings. These are accordingly the intake and exhaust valves.
The intake and exhaust valves operate at different times depending on the cycle of the engine. These valves are normally held closed by heavy springs and by compression in the cylinder. The purpose of the valve actuating mechanism is to overcome the spring pressure and open the valves at the proper time. The valve actuating mechanism includes the engine cam shaft, cam shaft borrowers (tappets), push rods, and rocker arms. The cam shaft is generally enclosed in the engine block or cylinder head. It has eccentric lobes (cams) ground on it for each valve in the engine. As the cam shaft rotates, the cam lobe moves up under the valve tappet, exhibiting an upward thrush through the tappet against the valve stem or push rod. This thrust overcomes a valve spring pressure as well as a gas pressure in the cylinder, causing the valve to open. When the lobe moves from under the tappet, the valve spring pressure reseats the valve, closing the opening.
In the intake cycle of the four strokes cycle, the intake valve is opened and the exhaust valve is closed allowing the entrance of the fuel air mixture into the cylinder. In the compression cycle of the four strokes cycle, both the intake and exhaust valves are closed. In the power cycle, both the intake and the exhaust valves are closed and a spark from the spark plug inside the cylinder head ignites the fuel air mixture powering and moving the piston downward. In the fourth stroke, the exhaust stroke, the piston is moved back upward from the crank shaft and the exhaust valve is opened and the intake valve is closed so that the piston can push out the exhaust fumes from the previous power combustion which exits the cylinder head through the exhaust manifold. The four stroke cycle is then repeated numerous times for the powering of the crank shaft.
The duration of the opening and closing of the intake and exhaust valves are fixed depending on the configuration of the cam lobe which lifts the valve tappets and accordingly opens the intake and exhaust valve. The fixed duration which the intake and exhaust valves are open is only optimal for one particular revolution per minute (rpm) of the crankshaft. This is generally set at around three thousand five hundred rpms. However the amount of the fuel/air mixture and consequently the exhaust fumes varies depending on the particular rpms that the automobile is operating. The optimal air to gas ratio is 14.7 parts air to 1 part fuel. Thus as more fuel is required at higher rpms a considerable volume of fuel and air is required to pass through the intake valve. Also, at lower rpms only a small volume of air and fuel is required to pass through the valve and with the valve required to remain open for a fixed period, the air/fuel mixture has a tendency to blow out of the cylinder back into the intake manifold. This phenomenon is known as blow back. Thus, with a pre-defined valve opening duration the intake and exhaust valves either stay open too long or not long enough depending on the rpms of the automobile.
Another problem associated with intake and exhaust valves is that they require cavity's to be established within the cylinder head creating a dimpled interior within the combustion chamber. Thus, when the spark plug emits a flame to ignite the fuel/air mixture, there exists uneven flame propagation and some of the fuel/air mixture does not combust. Furthermore, when some of the fuel/air mixture does combust, some of the heat energy is directed to the valve cavities and away from the piston. Both of these situations result in an inefficient combustion of the fuel/air mixture.
Previously, U.S. Pat. No. 5,103,780 discloses using a variable valve control which varies the duration which the intake and exhaust valves simultaneously remain open in a valve overlap condition in conjunction with a standard valve structure. U.S. Pat. No. 996,339 illustrates a valve system Which utilizes a rotating sleeve enclosed within the cylinder mechanically regulated by the crankshaft for aligning sleeve apertures with the intake and exhaust ports.
Accordingly, it is an object of the present invention to provide a valve system for opening and closing the intake and exhaust valves of an internal combustion engine that will enable the internal combustion engine to operate efficiently over a large range of RPMS;
Additionally, it is an object of the present invention to provide a simplistic intake and exhaust valve system which will require few moving parts and consequently weigh less and operate with less wear;
Furthermore, it is an object of the present invention to provide an internal combustion having the ability to have its intake and exhaust valves open at variable durations depending upon the efficient needs of the internal combustion engine;
Also, it is an object of the present invention to provide a simplistic intake and exhaust valve system which will provide for a small compact combustion chamber inside the cylinder head thus promoting a more efficient burning of the fuel/air mixture.